PZM-11 crosstalk

I used a PZM-11 in different rooms to record interviews, a RDL STM-2 preamp was used to phantom powered the mic and convert the mic signal to line level, all the RDL STM-2 was powered by a single 24VDC PW, in this configuration I was getting serious cross talk problems, I then used a separate 24VDC adapter for each mic and the cross talk problem went away, I'm scratching my head as to why the PW would make a difference, I'll be greatly appreciated if someone can explain this to me.

I do not know for sure, but my best guess is something to do with how the RDL STM-2 handles the ground plane internally. What exactly is the "PW" power supply anyway? I can't find it on the RDL site, so I don't know what it is. Where you using the balanced signal output, or where you having to "un-balance" it? That could make a difference as well.

I do not know for sure, but my best guess is something to do with how the RDL STM-2 handles the ground plane internally. What exactly is the "PW" power supply anyway? I can't find it on the RDL site, so I don't know what it is. Where you using the balanced signal output, or where you having to "un-balance" it? That could make a difference as well.

Thanks for your help, PW is just a 24VDC power supply not a particular RDL product and I'm using the balanced signal output, funny thing is that I had phantom-powered several Crown PZM 180 microphones (using a RDL STM-1) before and didn't have any cross-talk problem, by the way any suggestion of mic preamp other than RDL ?